With the continuous development of communication technology, antenna has gradually developed in the technical directions such as miniaturization, wide frequency band, various wave band, and high gain. Compared with the conventional horn antenna, helical antenna, and dipole antenna, liquid crystal antenna is a kind of antenna which is more suitable for the current technical development directions.
Generally, a liquid crystal antenna includes a transmitting patch, a grounded electrode and liquid crystal located between the transmitting patch and the grounded electrode. When electromagnetic wave of a specific frequency is transmitted to the liquid crystal antenna, the electromagnetic wave of the specific frequency can be radiated by the liquid crystal antenna if the specific frequency is in accordance with the resonant frequency of the liquid crystal, while the electromagnetic wave of the specific frequency cannot be radiated through the liquid crystal antenna if the specific frequency is not in accordance with the resonant frequency of the liquid crystal. Besides, because a variation of orientation of the liquid crystal will result in different effective dielectric constants and thus a variation of the capacitance, the orientation of liquid crystal between the transmitting patch and the grounded electrode can be adjusted by the voltage applied on the transmitting patch, so as to adjust the resonant frequency of the liquid crystal antenna.